GRIK2 (GluK2-containing kainate receptor)

Class

AAV9 gene therapy delivering engineered miRNAs that silence GRIK2 via RNA interference (not a classical small-molecule or antibody mechanism)

Pathway

locally suppresses aberrantly expressed GluK2-containing kainate glutamate receptors in the epileptic hippocampus, believed to trigger seizures in refractory mesial temporal lobe epilepsy

GRIK2 encodes GluK2, a subunit that assembles into kainate receptors, a subtype of ionotropic glutamate receptor that responds to the excitatory neurotransmitter glutamate by opening a channel that admits positively charged ions, depolarizing neurons. In some cases of mesial temporal lobe epilepsy, a form of epilepsy centered on hippocampal circuits, GluK2-containing kainate receptors are expressed at abnormally high levels in affected brain tissue, and this aberrant expression is thought to sustain the runaway neuronal excitability that produces seizures, particularly in patients whose seizures no longer respond to standard antiseizure medications. Rather than blocking the receptor pharmacologically, this approach uses a gene therapy strategy: an adeno-associated virus (AAV9) vector delivers a small engineered RNA molecule designed to trigger the cell's natural RNA interference machinery, degrading the messenger RNA that codes for GluK2 and thereby reducing its production directly at the source. Because delivery can be restricted to affected tissue, the intent is durable, localized suppression of the abnormal receptor population rather than transient, body-wide receptor blockade. This mechanism matters broadly for drug-resistant focal epilepsies, where existing therapies act on ion channels or neurotransmitter systems generally rather than correcting a localized molecular abnormality believed to drive the seizure focus itself.